A major cause of errors in person perception is identification-inference nonindependence, that is, the use of the same sources of information to identify behavior and to make further inferences about its causes. The present research will investigate the antecedents and consequences of identification-inference nonindependence in judgements about personal dispositions. In this domain, nonindependence occurs to the extent that information about situational pressures and prior beliefs about the target's personality (priors) affect both identification of the behavior and inferences about the target's personality. Nonindependence can produce systematic biases. In particular, nonindependence augments perceiver's reliance on their prior beliefs about the target person and undermines proper utilization of information about situational pressures. The proposed research will investigate nonindependence in both self perception and other perception. The self perception studies will investigate how placebo treatments affect identification of psychological symptoms and inferences regarding the underlying psychopathology. The other perception studies will study identification and inferential effects of stereotype- based expectancies and information about situational pressures (e.g., group pressure). Together, the proposed studies should increase our understanding of how low-level identification processes and high-level inference processes contribute to biased and unbiased judgements about our own and others' personal dispositions.